[Bug]: student signup validates current_year but never stores it in the database

[anshul23102]

Bug Summary

In backend/controllers/auth.controller.js, the student signup path validates current_year (checking that it is between 1 and 6) but never includes it in the User.create call. Every student account created through signup will have current_year as undefined in the database, even though the field exists in studentBioSchema and the client submits a value.

Steps to Reproduce

1. Send a POST request to the signup endpoint with:
   • userType: 'student'
   • current_year: 3
   • Valid values for all other required fields
2. The request passes the current_year validation check (1 <= 3 <= 6)
3. Check the created user document in MongoDB
4. Observe that student_bio.current_year is undefined (not stored)

Expected Behavior

The validated current_year value (e.g., 3) should be persisted in student_bio.current_year of the newly created user document. Any feature that reads current_year (such as year-based access controls or academic year calculations) should receive the value the student submitted.

Actual Behavior

The User.create call for student signup builds student_bio as follows:

student_bio: {
  gender: req.body.gender || 'male',
  enrollment_year: req.body.enrollment_year || new Date().getFullYear(),
  course: course_id,
  roll_number: req.body.roll_number || null,
  avatar: ''
}

current_year is absent from this object. Despite passing validation, it is silently discarded. The studentBioSchema defines the field with min: 1, max: 6, so the schema already supports it - it is only the controller that omits it.

Environment

• Backend: Node.js / Express
• File: backend/controllers/auth.controller.js (student signup branch)
• Model: backend/models/User.model.js (studentBioSchema.current_year)

Additional Context

The fix is a one-line addition inside User.create:

student_bio: {
  gender: req.body.gender || 'male',
  enrollment_year: req.body.enrollment_year || new Date().getFullYear(),
  current_year: req.body.current_year,   // add this line
  course: course_id,
  roll_number: req.body.roll_number || null,
  avatar: ''
}

Expected NSOC points: Level 2 (medium complexity - validated input silently dropped at the persistence layer)

Suggested labels: bug, NSOC'26, level2

Checklist:

• Searched existing issues - not a duplicate
• Read CONTRIBUTING.md and project rules (issues 🚨 Issue Creation & Assignment Rules (Important) #74 and 🚨 Mandatory Onboarding – Read Before Contributing #75)
• Provided clear reproduction steps
• No AI/Claude mentions
• No em dashes or double hyphens
• Repository verified as NSOC

[anshul23102]

@omkarhole Could you please /assign this issue to me? I'd like to work on it under NSOC '26.